| Abstract: | A process for preparing fish protein concentrate (FPC) with rehydration and emulsifying properties is described. Micropogon undulatus, which is discarded during shrimping operations in the Gulf of Mexico, is used as a starting material. Theoretical aspects of maintaining functional properties in hot solvent extracted proteins are discussed. The rehydration and emulsifying capacities of fish protein are maintained by pH adjustment to prevent protein-protein interaction during hot solvent extraction processes. The process for preparing FPC from 100 g of fish muscle consists of the following steps: (1) comminution with 5 g of NaCl, (2) adjustment of pH to 2.5 with 1N HCl, (3) extraction of lipids with 400 ml of 1:1 mixture of 95 percent ethanol and hexane by refluxing at 70°C for 30 minutes, (4) removal of solvents by filtration or centrifugation, (5) repetition of the steps 3 and 4 until most of the lipids are removed and (6) drying of FPC below 70°C in air or vacuum. The FPC produced by this method has the following qualities: (1) amino acid spectrum similar to that of the fish muscle, (2) bacteriologically sterile, (3) water retention capacity at least twice the capacity of the original fish muscle, (4) forms emulsions in oil-water mixtures, (5) has high protein efficiency ratio, (6) appears to be useful as a binder protein in sausage-like products and (7) forms milk-like suspensions. A partially refined fish oil is produced as a co-product. The process removes Pb, Cd and As from fish muscle but not Hg. The Hg in FPC is rapidly incorporated into and retained by the blood, kidneys and livers of rats. |
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